FIG. 1 depicts a diagram of the salient components of wireless telecommunications system 100 in accordance with the prior art. Wireless telecommunications system 100 comprises: wireless terminal 101, base stations 102-1, 102-2, and 102-3, wireless switching center 111, assistance server 112, location client 113, and Global Positioning System (“GPS”) constellation 121. Wireless telecommunications system 100 provides wireless telecommunications service to all of geographic region 120, in well-known fashion.
The salient advantage of wireless telecommunications over wireline telecommunications is the mobility that is afforded to the users. On the other hand, the salient disadvantage of wireless telecommunications lies in that fact that because the user is mobile, an interested party might not be able to readily ascertain the location of the user.
In some cases, the owner/operator of wireless telecommunications system 100 might desire to charge its customers different rates depending on where they are at the time that they are using its service. For example, to better compete with land-based wireline telephone service, the owner/operator might desire to charge its customer a lower rate when they are at home and a higher rate when they are out shopping. In this case, the owner/operator might define the customer's home as a “zone” and charge less for calls made from that zone. The efficacy of this idea requires, however, a technique for estimating when a wireless terminal is in a zone and when it is not.